Solvent refining with nitro-alcohols



Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE SOLVENT REFINING WITH NITRO-ALCOHOLS of Delaware N Drawing. Application November 3, 1933, Serial No. 696,539

4 Claims.

This invention relates to refining hydrocarbon oil, and more particularly to refining mineral oil by solvent extraction.

The invention contemplates the treatment and 5 refining of mineral oil with a selective solvent whereby the oil is separated into fractions having desired characteristics.

The invention has particular reference to the extractive treatment of mineral oil with nitrobenzyl alcohols and which have the following chemical formula:

These alcohols exist in the ortho, meta or para forms, and the invention contemplates extracting oil with any one of the three forms, or their isomers, or with mixtures of any two or more of them or their isomers.

The foregoing solvent liquids are suitable for extracting undesired constituents from mineral oils, and particularly from lubricating oil fractions.

Lubricating oils, such as produced from Mid- Continent crude, are ordinarily composed of relatively paraffinic constituents, and also relatively non-parafiinic constituents, including naphthenic, aromatic, and unsaturated hydrocarbon bodies. The solvent of my invention is adapted to extract these relatively non-parafiinic bodies from the oil for the production of lubricating oil fractions which are of relatively high paraflinic character, and therefore of relatively higher viscosity index than the untreated oil.

In the application of my invention to the treatment of mineral oils for the production of lubricating oil, one part of the oil is mixed with about two parts of solvent liquid, and this mixture is then subjected to agitation and heating in order to effect solution of the undesired constituents of the oil in the solvent. The extent to which the oil is soluble in the solvent will depend upon the nature of the oil as well as upon the condition of temperature and pressure employed. The conditions of temperature and pressure, as well as the ratio of solvent to oil, may be varied for the purpose of effecting the particular degree of extraction desired. The temperatures employed will depend upon the nature of the oil undergoing treatment, the degree of separation desired, and also, to some extent, upon whether the solvent is used alone or in combination with a modifying solvent or diluent, as hereinafter mentioned. Thus, in the case of para-nitro-benzyl alcohol, it may be desirable to employ temperatures of around 200 F. or higher, the upper limit depending upon the point at which complete miscibility of the solvent with the particular 6 fraction of oil undergoing treatment is reached.

Upon settling, the mixture separates into two layers, one of which comprises the constituents Which it is desired to extract from the oil dissolved in the bulk of the solvent liquid, while 10 the other layer comprises the undissolved and relatively paraffinic oil in admixture with a relatively small amount of solvent.

The two layers are then separately withdrawn,

and the solvent liquid recovered therefrom. If 15' desired, the separated layers may be subjected to treatment with additional quantities of the W solvent for the purpose of obtaining a series of fractions of differing characteristics.

By way of specific example, a dewaxed dis- 20 tillate fraction, derived from Mid-Continent crude, was mixed with para-nitro-benzyl alcohol in the proportion of two parts of solvent to one part of oil. After complete mixing, the mixture was allowed to stand at atmospheric pressure 25 and while maintained at a temperature of about 212 F. Under these conditions, the mixture of oil and solvents separated into a rafilnate portion containing of the original oil and an extract portion containing the remainder of the 30 oil dissolved in the solvent. The resulting raffinate possessed a marked improvement in viscosity index and color.

In some instances, it may be of advantage to carry out the extraction in the presence of a 35 modifying solvent liquid, such as benzol or a light petroleum naphtha, or a petroleum fraction composed of propane or other similar low boiling hydrocarbons, for the purpose of facilitating the extraction and further controlling the extent 40 thereof.

The lubricating oil distillate may be subjected to the foregoing extraction treatment, either before or after dewaxing, or subsequent to treatment with other solvents or chemicals. 5

The invention is not necessarily limited to the treatment of lubricating oil fractions, since the solvent may be adapted to the refining and purification of various hydrocarbon or mineral oil fractions, including naphtha, cracked naphtha, 50 kerosene, etc., as well as residual or distillate fractions, or products derived from petroleum or other sources.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may 55 be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. The method of refining hydrocarbon oil containing relatively paraffinic and relatively non-paraflfmic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-parafiinic constituents therefrom, which comprises extractively treating the oil with nitrobenzyl alcohol whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

2. The method of refining hydrocarbon oil containing relatively paraffinic and relatively non-parafiinic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-parafiinic constituents therefrom, which comprises extractively treating the oil with ortho nitrobenzyl alcohol whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

3. The method of refining hydrocarbon oil containing relatively parafiinic and relatively non-parafiinic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-parafiinic constituents therefrom, which comprises 'extra'ctiv'ely treating the oil with meta nitrobenzyl alcohol whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

4. The method of refining hydrocarbon oil containing relatively paraflinic and relatively non-paraflinic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-paraflinic constituents therefrom, which comprises extractively treating the oil with para nitrobenzyl alcohol whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

LOUIS A. CLARKE. 

